This invention relates to quick disconnect couplings for connecting and disconnecting hydraulic lines. More particularly, the invention relates to a lever-operated female quick disconnect coupling.
Quick disconnect couplings are conventionally used for connecting hydraulic lines which are used, for example, on agricultural tractors. A female coupling is generally mounted on the tractor and is connected to the hydraulic system of the tractor. A mating male coupling is mounted on the hydraulic hose of an agricultural implement which is to be towed by the tractor, and the hydraulic system of the implement can be connected to the hydraulic system of the tractor by connecting the two couplings.
Conventional quick disconnect couplings cannot be connected and disconnected when the couplings are pressurized with hydraulic fluid. Lever-type couplings are available in which the female coupling is provided with a lever for providing a mechanical advantage in opening the valves when there is trapped hydraulic pressure in either or both couplings. Lever-type couplings are shown in my co-pending application Ser. No. 832,182, filed Sept. 12, 1977 and in U.S. Pat. Nos. 4,009,729, 3,710,823 and 3,166,343.
Most lever-type quick disconnect couplings have one or more of the following disadvantages:
1. Excessive oil spillage during each disconnection. The large volume of oil between the valves is spilled during each disconnection.
2. High pressure drop caused by long turbulent flow passages.
3. High pressure drop caused by the lever-operated cam of the coupling being located between valves of the two couplings, which is at the most flow-restrictive location.
4. High manufacturing cost due to extra long parts, complicated shapes, and large number of parts.
5. The cam works directly on the valve ball, which limits the design to ball-type valves. Due to the metal-to-metal sealing characteristics, ball-type valves can leak.
My new coupling overcomes these limitations in the following ways:
1. The cam is located at the rear portion of the valve assembly where the flow passage is large. This minimizes flow restrictions and pressure drop.
2. Since the cam is not working directly on the sealing end of the valve assembly, there is more flexibility in valve design. Thus, a soft-seat valve is used to eliminate leakage.
3. Since the force applied against the male coupling is linear, the female coupling will work with poppet-type as well as ball-type male couplings. The cam as used in U.S. Pat. Nos. 3,166,343 and 4,009,729 will work only on ball-type valves due to the cam rotational force.
4. The design minimizes the number of parts, and the parts are short in length. Therefore, manufacturing costs are minimized.
5. The design permits a dual angle cam to gain mechanical advantage in opening against internal pressure and maintaining a short lever length.